<target name="check_endorsed">
    <condition property="endorsed.exists">
      <and>
        <available file="${endorsed.dir}/xalan.jar"/>
        <available file="${endorsed.dir}/dom3-xml-apis-2.5.0.jar"/>
        <available file="${endorsed.dir}/dom3-xercesImpl-2.5.0.jar"/>
      </and>
    </condition>
    <fail unless="endorsed.exists">
      Your Java endorsed folder does not contain all the necessary jar files!
      Run the dist target and then copy all the jar files from dist/endorsed to:
      ${endorsed.dir}
    </fail>
</target>